TEXAS INSTRUMENTS LM358AD IC, OP-AMP, 700KHZ, 0.3V/us, SOIC-8

In this tutorial I'm going to talk about operational amplifiers, or "op amps" because they are the easiest type of amplifier for beginners to work with. I will also show you a microphone amplifier circuit that you can build to listen to your heartbeat or spy on people that you don't like. So what is an amplifier? Generally speaking, an amplifier takes a small voltage on the input and puts out a bigger voltage on the output. The "gain" of the amplifier is the amount that you're multiplying the voltage by. For example here is an amplifier that takes one volt on the input and gives five volts on the output. So we say this amplifier has gain of five. Now the diagram I'm using here with the triangle is just a simplified symbol so let's take a look at a more formal circuit diagram. A bare operational amplifier will have five important pins. Over here we have the output pin. Your output voltag